Watermelon is an important horticultural crop with over 137,000 acres grown in the United States in 2005. The leading watermelon producing states are Florida, Georgia, Texas, and California with a combined total of 86,300 acres. (National Agricultural Statistics Service of USDA—January 2006)
The popularity of seedless (triploid) watermelon has increased over the last decade. During peak watermelon production in the U.S. market in 2005 and 2006, seeded watermelons only comprised 22% of the market and averaged four to five cents less per pound (Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, HS1079, January 2007).
Population of the United States is estimated at over 300 million as of July 2007 (Central Intelligence Agency website).
Of the 20.8 million Americans with diabetes, 90 to 95 percent have type 2 diabetes. (American Diabetes Association website). This amounts to 7% of the total population of the United States.
The glycemic index (GI) is a ranking of foods on a scale from 0 to 100 according to the extent to which they raise blood sugar levels after eating. Foods with a GI of 70 or above are considered high GI foods. Watermelon is rated at 72 which is considered a high GI. (University of Sydney Glycemic Index and GI database)
Glycemic index in watermelon can be lowered by decreasing its sugar content.
Lower GI foods have been shown to help control type 2 diabetes and improve weight loss. (Harvard School of Public Health—website)
The goal of plant breeding is to combine in a single variety or hybrid various desirable traits. Desirable traits may include resistance to diseases and insects, tolerance to heat and drought, reducing the time to crop maturity, greater yield, and better agronomic quality. Other desired traits may include particular nutrient content, color, fruit shape, as well as taste characteristics.
As with many different plants, watermelon contains a fruit part and a plant part. Each part contains different traits that are desired by consumers and/or growers, including such traits as flavor, texture, disease resistance, and appearance traits such as shape and color. Reduced sugar is a highly desirable trait for consumers with type 2 diabetes. The seedless trait in the watermelon fruit is also highly desired by consumers. Extended flowering in diploid watermelon plants is a trait sought after by growers of seedless watermelon.
Seeded watermelon plants are diploid and can be self-pollinated either by bees or by hand.
Seedless watermelon plants are triploid and must be pollinated by the pollen of diploid watermelon plants. The two primary methods currently in practice to pollinate seedless watermelon plants are; 1) planting traditional hybrid diploid varieties (e.g. Sangria produced by Syngenta, Inc.) in dedicated rows and harvesting and selling both the diploid fruit and the seedless fruit, or 2) inter planting between triploid watermelon plants within rows of triploid plants special pollenizer plants (e.g. SP-1 produced by Syngenta, Inc.), with plant characteristics especially favorable for pollination, which produce non-marketable fruit due their poor fruit quality, in particular a thin explosive rind making it difficult to harvest and transport the fruit. Due to the non-marketable fruit that these special pollenizer plants produce, they are generally referred to as “Non-Harvestable Pollenizers”.
The present invention recognizes the need to provide consumers with type 2 diabetes a watermelon with reduced sugar and therefore with less total carbohydrates, and a lower glycemic index. The present invention also recognizes that a method of producing reduced sugar watermelons is needed that reduces the economic risk of producing this product which has a relatively limited market (less than 7% of the total market).